Case Study River Tees

Question 1

Location?

Answer 1

North-east England

Question 2

Background info?

Answer 2

Source in Penine Mountains - flows east towards North Sea

Question 3

Upper course: river valley - shape?

Answer 3

V shaped valley as due to river’s high altitude it has large amount of GPE and uses this energy to erode downward (vertical erosion) creating narrow steep-sided gorge.
The sides of gorge collapse due to their own weight and due to weathering creating a v-shaped valley.

Question 4

Upper course: valley - interlocking spurs?

Answer 4

River is forced to wind around hills because it does not have enough energy to remove them by sideways (lateral) erosion so instead creates interlocking spurs.

Question 5

Upper course: landforms - waterfall?

Answer 5

• High Force waterfall and gorge formed (tallest in England at 21M).
• Made of cap of hard rock (Whinsill) and softer rocks below (limestone, sandstone and shale)
• Soft rocks eroded more quickly causing undercutting and hard rock overhangs, eventually collapsing due to gravity
• Waterfall retreats, creating a steep sided gorge

Question 6

Upper course: Landforms - pot holes at Low Force?

Answer 6

• Pebbles of resistant Whinsill become trapped in hollows in river bed
• As river flows over these pebbles it forces them to swirl around and bedrock is worn away by abrasion making hollow wider and deeper
• These enlarged hollows are known as pot holes

Question 7

Middle course: valley - shape?

Answer 7

• Wider, flat bottomed valley
• As river altitude decreases, the river has less GPE and so less vertical erosion occurs
• Instead river uses energy to erode sideways (laterally) and river valley gets wider w flat valley floor

Question 8

Middle course: valley - bluffs?

Answer 8

River has enough energy to erode laterally and wear away hills that protrude into the river valley (interlocking spurs).
This leaves a line of hills on either side of the river valley known as bluffs.

Question 9

Middle course: landforms - meanders?

Answer 9

• Near Barnard Castle
• Fast water on outside of bends in river erode rapidly (hydraulic action and abrasion) forming a river cliff
• Slower water on inside of bends deposits material forming a slip-off slop
• Bends in the river become more pronounced and sides of the river valley undercut, collapse and retreat so river valley becomes wider

Question 10

Middle course: Landforms - floodplain?

Answer 10

• Near Barnard Castle
• When the river level rises, the surrounding land is flooded
• Sediment transported in suspension is deposited as the speed of the water flow decreases
• Every time the river floods, a new layer of slit is added to the floodplain

Question 11

Lower course: valley - shape?

Answer 11

Very wide, flat-bottomed w bluffs. The river continues to erode laterally, widening the river valley.

Question 12

Lower course: landforms - levees?

Answer 12

• When the river floods, the biggest, heaviest material is deposited first, closest to the original river channel
• Over time this builds to form a bank on either side of each channel known as a levee
• Depostion on the original river bed leads to it flowing above the height of floodplain
• When river now floods, it can no longer flow back into river

Question 13

Lower course: Landforms - ox-bow lakes?

Answer 13

• Close to Yarm
• As meanders become more exaggerated due to erosion on outside and deposition on inside of bend, the meander neck narrows
• Eventually river breaks through the neck often during time of high discharge (flooding)
• Deposition in the entrance and exit to old meander results in it eventually being cut off as a crescent shaped lake called an ox-bow lake
• Over time this dries out due to evaporation